1. Field of the Invention
The present invention relates to a stencil stamp assembly, and more particularly, to a stencil stamp assembly provided with a thermal stencil sheet forming a stamping part.
2. Description of Related Art
Stamps provided with a rubber stamping member have been used for stamping the surface of a sheet with company names, addresses and the like in character strings. Generally, stamps for such uses are made individually to order. As a result, the stamps are relatively expensive, and it requires a relatively long time to procure a stamp after placing an order.
A thermal stencil sheet has been practically used on stamp assemblies in place of the rubber stamping member. Pores, or holes, can be formed in a desired pattern in the thermal stencil sheet by irradiating the thermal stencil sheet with an infrared beam or by using a thermal head. Various patterns including character strings, figures, marks and such may be formed on a recording sheet by pressing ink out through the pores of the thermal stencil sheet onto the recording sheet.
A stencil stamp assembly comprising, as principal components, the aforesaid thermal stencil sheet and an ink-bearing member impregnated with ink is disclosed in Japanese Utility Model Laid-Open Publication No. 5-74833. The stencil stamp assembly is suitable for replacing a stamp provided with a rubber stamping member as a stamping part.
The prior art stencil stamp assembly includes a stencil stamp block fabricated by attaching an ink-bearing member impregnated with ink to a frame that surrounds the ink-bearing member, then adhesively attaching a thermal stencil sheet to the frame so that the thermal stencil sheet covers the ink-bearing member.
When using the stencil stamp block on a stencil stamp assembly, the stencil stamp block is adhesively attached to a cushion member on a lower surface of the base of a handgrip on the stamp assembly. Character strings or the like are formed in a desired pattern in the thermal stencil sheet with infrared beams or a thermal head. The resulting stamp assembly is capable of stamping many copies of the desired pattern on a recording sheet. The stamp assembly provided with this stencil stamp block will hereinafter be referred to as a "stencil stamp."
The prior art stencil stamp, which has a thermal stencil sheet placed over the lower surface of the ink-bearing member, has a unitary stamping part, and the stencil stamp block is formed in a single unit. Accordingly, a user may encounter the following inconveniences when using the prior art stencil stamp.
If the stamping part of the stencil stamp is partly broken, the entire stencil stamp becomes inoperable, even if the other components of the stencil stamp remain operable. The entire stencil stamp block of the stencil stamp must be replaced with a new stencil stamp block to restore the stencil stamp to its normal state.
If a portion of the pattern of pores formed in the stamping part of the thermal stencil sheet of the stencil stamp must be changed, the entire stencil stamp block must be replaced with another stencil stamp block having a stencil sheet with the desired pattern of pores, even if portions of the original stencil sheet need not be changed. This is necessary because once the pattern of pores is formed in a thermal stencil sheet, the pattern cannot be changed.
Because the stencil stamp block has only a single ink-bearing member impregnated with ink of a single color, a multicolor image cannot be created by a single stamping action.
When it is desirable to stamp only a portion of the pattern formed in the stencil sheet of the stamping part, the undesired portions of the stamping part must be masked with a separate piece of paper or the like, which is troublesome.